Multi-Hazard Design To Improve Facility Resilience

Increasing Building Resilience

There are several organizations advocating for increased resilience in buildings, facilities, and communities to increase our ability to recover from damaging events. One of these organizations is the National Institute of Standards and Technology, which manages a multifaceted community resilience program. Advocating for increased community resilience can take many forms, including strengthening building codes, improving local and regional infrastructure, and enhancing emergency preparedness and response recovery plans.

For many, the sheer magnitude of the issue and the multitude of "moving parts" can be intimidating and may serve as an impediment to confronting the resilience issue. A typical conversation with a facility owner and/or risk manager about the resiliency of their building or facility may start with a discussion of the design standards for their buildings and equipment, emergency preparedness, response recovery plans that they have in place, and the robustness of the different external services (e.g., utilities) that are required to keep their facility operational. The conversation then often segues into a discussion regarding how (or if) the external utility service providers are protecting their assets. From there, the issue "expands" significantly and may leave an owner or risk manager feeling overwhelmed with a sense of frustration about how they can focus on such a large and complicated issue.

Incorporating Safety Standards

A good starting point for many facility owners and risk managers is to consider how they specify and design new buildings, structures, and infrastructure within their own facilities. Often owners will hire an architectural firm or other design consultant and leave the details of the design to that professional with the understanding that the final design will meet all of the local "code" requirements in addition to any functional requirements needed for operation of the facility. What is often missed in this standard practice is the owner's opportunity to cost-effectively enhance the resilience of the building, structure, or infrastructure against effects from potential natural hazards during the initial design, which in turn will increase the resilience of their overall operations.

An example is a planned building in a moderate or high seismic hazard region (this covers a large portion of the United States, as shown below) that may also experience extreme wind loads and/or flooding hazards over the life of the building. Conventional loads, which include wind and seismic loads (for life safety) are specified in the International Building Code (the typical building code used throughout the United States). Other more extreme loads, such as tornadic wind and extreme hurricane wind forces, are not explicitly specified in the building code. While the standard seismic design of a building or structure may result in a more robust lateral load-resisting system, it may not fully protect the building or structure from the extreme wind (or flood) loads. Items such as uplift restraint of key structural members, more robust cladding and fenestration elements, and heavier roofing elements will all need to be considered.

2014 Seismic Hazard Map (Peak Ground Acceleration, 2 percent in 50 years)

Source: United States Geological Survey, October 2017

Those familiar with the Federal Emergency Management Administration (FEMA) requirements for storm shelter design may recognize the shelter design wind speed map shown below. The figure provides a good illustration of those areas in the United States that are at risk from extreme wind loads. If those "at-risk" regions depicted in the map below are compared to the regions of moderate to high seismic hazard shown above, it is easy to see that there is considerable overlap between regions of moderate to high seismic hazard and those regions at risk from extreme winds.

Design Wind Speeds for Community Shelters Map

Source: FEMA, October 2017

The key is that, for a new building already being designed for moderate or high seismic loads, the increased cost to an owner to provide the additional enhancement for extreme wind (or flood) may be small—compared to the overall project cost—while greatly enhancing the resilience of the building, facility, and possibly the overall community.

Conclusion

When planning for new buildings, structures, or infrastructure projects, facility owners and risk managers should insist that the design teams consider all reasonable events that may impact their facility and investigate the nominal cost increase to provide the additional resilience in their designs. One day, this added resilience could allow their facility (and their community) to recover more quickly from a catastrophic natural hazard event.